Warcraft III: Reign of Chaos is a real-time strategy game developed and published by Blizzard Entertainment, released in July 2002. It is the third main entry in the Warcraft series, set in the high fantasy world of Azeroth. The game features four playable races: Humans, Orcs, Night Elves, and Undead, each with distinct units, heroes, and playstyles. The single-player campaign spans multiple missions, each focusing on a different race, and follows a complex narrative involving the return of the demonic Burning Legion. A major innovation is the introduction of hero units that gain experience and levels, carrying over between missions. The game also emphasizes small-scale tactical combat over large armies, with mechanics like unit upkeep and spell autocasting. Multi-player includes competitive ranked play and custom map-making tools. Warcraft III received universal acclaim for its graphics, gameplay depth, and story, and its legacy includes spawning the popular Defense of the Ancients (DotA) mod genre. An expansion, The Frozen Throne, was released in 2003.